The present invention relates to leg-compressing or anti-embolism stockings.
It is known that it is desirable for various medical purposes to apply pressure to a patient's leg in order to control the blood supply of the vascular system in the leg. For example, blood may tend to pool in the vessels of a patient's feet, and it is desirable to inhibit this pooling and force the blood to a more even distribution over the patient's legs. For this purpose it is usually desirable, to achieve optimum results, that a pressure be exerted on the leg which decreases from the foot to the top of the leg. The desired pressure application can be achieved by wrapping elastic bandages around the legs, but this requires application by skilled personnel and can be quite time-consuming, and bandages tend to slip on the leg, resulting in undesirable shifting of the pressure distribution and the leaving of constriction wrinkles on the user's leg.
In order to avoid these disadvantages, elastic stockings have been developed. While such stockings are much easier to use than elastic bandages, there has not been developed a stocking which achieves the desired pressure distribution on the leg, with the pressure decreasing from the ball of the foot to the upper end of the stocking.
One such elastic stocking is disclosed in British Patent No. 1,445,233, the complete specification of which was published on Aug. 4, 1976. That patent discloses a rotary knitted integral one-piece stocking in which there are variations in the circumferential tension along the length of the stocking tube. But in that stocking the tension is greatest at the calf portion of the stocking, the tension decreasing from there toward the thigh portion and toward the foot portion of the stocking. A copy of that prior patent is filed herewith.
Other stockings achieve a pressure decrease which begins at the wearer's ankle and thus does not solve the problem of pooling of blood in the feet.